While current Claus sulfur condenser structures have proven satisfactory for condensing sulfur, there is a need for improvement in the quality of the sulfur condensed. FIG. 1 depicts a prior art vertical Claus sulfur condenser 2 in which Claus process gas 4 from a reaction furnace or a catalytic reactor enters condenser 2, passes through tubes 6, which are submerged in a cooling media, which is usually boiling water. At a bottom location, Claus process gas 8 then exits vertical Claus sulfur condenser 2 to a downstream reaction stage. Boiling water 10 may enter Claus sulfur condenser 2 at a location 12 and exit at a location 14 to aid in condensing within Claus sulfur condenser 2. Condensed liquid sulfur 16 drains from inside tubes 6 and falls to a bottom Claus sulfur condenser 2 and exits through a bottom location 18.
FIG. 2 depicts a prior art horizontal Claus sulfur condenser 20 in which Claus process gas 22 from a reaction furnace or a catalytic reactor enters condenser 20 at a location 23, passes through tubes 24 submerged in a cooling liquid, which is usually boiling water. Claus process gas 22 then exits at a location 25 to a downstream reaction stage. Water 26 enters Claus sulfur condenser 20 at a location 28 and exits at a location 30 to aid in condensing Claus process gas 22 within tubes 24 of Claus sulfur condenser 20. Liquid sulfur 32 that condenses within tubes 24 then falls and exits Claus sulfur condenser 20 through a bottom location 34.
During the process of conventional Claus sulfur recovery, a liquid sulfur product is produced that by the nature of the sulfur condensation process incorporates reactant hydrogen sulfide (H2S) into the sulfur as simple dissolved H2S and chemically bound H2S in the form of sulfanes, H2Sx, (with x>1). Traditionally, sulfur containing dissolved H2S and H2Sx stored for periods of time outside the Claus process will eventually lose the H2S to the gas above the sulfur liquid level in the storage vessel, such as a truck, rail car, tank, or underground pit. Sulfur in storage emanates the dissolved H2S from product sulfur because of the low solubility of simple dissolved H2S at ordinary liquid sulfur storage temperatures (250 F to 318 F), and the thermodynamic instability of the sulfanes with respect to H2S and elemental sulfur. Accumulations of emanated H2S can lead to unintended exposures during loading of sulfur and during storage of sulfur in open air containers, such as underground concrete pits that facilitate gravity drainage or tanks vented with air. Emanated H2S can also cause undesired mixtures to form in open air storage vessels.
Disposing of emanated H2S is another issue. Incinerating emanated H2S near or in front of a Claus sulfur plant stack generates SO2 emissions that are monitored for environmental compliance. In some instances, up to half of the reported emissions from a Claus sulfur recovery plant and Claus Tail Gas Cleanup unit can come from H2S emanated from liquid sulfur in storage. Under certain circumstances, these additional emissions may limit the sulfur processing capability of the Claus/TGU unit.
What is needed then is a device and process that does not suffer from the above disadvantages.